The end to the tests comes after months of negotiations to persuade companies to stop using animals - mainly guinea pigs, rats and mice - in the last remaining tests.

No fresh licences will be issued, meaning an effective ban, a Home Office spokesman said.

But the change will only affect a tiny fraction of laboratory animals - less than 0.1% of the 2.7m animals used in testing in the UK each year.

Many scientists say animal tests are vital for medical research

A spokesman for People for the Ethical Treatment of Animals said: "It is important to remember that this ban effects just the UK. We have to make sure that this is carried out abroad."

Campaigners are also likely to switch the spotlight on to the use of animals for testing in medical and veterinary research.

Winning a ban in these areas may prove more difficult to achieve, since large sections of the public are supportive of animal research if it will save human life.

Recently, concerns have been raised about the use of genetically modified animals in scientific research. Some of these animals have been "designed" to die from a specific disease, others, such as pigs, have been altered to provide "spare-part" organs in human transplants.

Last week, a leading group of scientists and thinkers - under the banner of the Church of Scotland - issued a report in which they said the medical benefits that stem from such research must be overwhelming to justify the use of transgenic animals.

In the future, the more general use of animals in scientific research may become unnecessary as new techniques are developed for growing human tissues in the lab.

These could be used to check the safety and effectiveness of many of chemicals that are now tested on animal models.